Tortoise SVN behaves sometimes pretty weird but not with respect to functionality but with display. Recently while playing with TSVN 1.5.5 and found that it is not displaying icons to show the file/folder status. I am running it on WinXP with sufficient memory on it.
In fact, displaying the status through Icon overlays is one of the key features with TSVN. After googling around for sometime and trying various options, zeroed down on one. The solution that worked for me included changing the "Cache status" from "Default" to "Shell".
Following image would show the new status. One can access Cache status by right clicking on the windows explorer --> Tortoise SVN --> Settings --> Icon Overlays